1. Field of the Invention
The invention relates to a vacuum cleaning system having a vacuum cleaner, particularly of the canister or tank type. Some of these cleaners are designed so that a hose assembly is attached to the tank at one end and a powered cleaning tool is attached at the other end of the hose assembly, with the motor in the tank providing the vacuum through the hose into the cleaning tool. The hose assembly is of the type having a cylindrical hose body which is reinforced by spaced helical coils that also serve as electrical conductors.
2. Prior Art Statement
Various devices for controlling power to powered vacuum cleaning tools, by utilizing an on-off switch, have been devised. Such switches have been mounted in the end connectors of the hose, such as shown in two inter-related patents to Wickham et al, U.S. Pat. Nos. 3,636,285 and 3,733,697, and in U.S. Pat. No. 4,277,640 to Kutnyak et al. It has also been known to install a fault interrupter device, as shown in Somers U.S. Pat. No. 4,283,594, and a thermal overload device as shown in Grabovez U.S. Pat. No. 4,168,564; both devices serving to disconnect power to a cleaning tool in the event problems are detected. Both these devices are also installed in the end connectors of the hose. It is also known to mount such a switch on a permanently assembled hose and handle as shown in Hetland U.S. Pat. Nos. 3,579,706 and 3,588,943.
In order to complete the electrical circuit from the vacuum cleaner to the cleaning tool, it has been a preferred practice to use a cord and plug arrangement, often called a "pigtail", such as shown in the Wickham, Somers and Grabovez patents, and as also shown in Kleykamp et al, U.S. Pat. No. 4,063,790. This pigtail is used both as a connector from the vacuum cleaner to the hose, and from the hose to the cleaning tool. At the same time, some type of mechanical interengagement is used in the above patents to lock the assemblies together while conveying air from the vacuum cleaner to the cleaning instrument. In one instance, an intermediate member is provided between the hose assembly and cleaning tool to provide both mechanical and electrical interengagement. This is shown in Holden et al, U.S. Pat. No. 4,188,081.